Watch white peach scale – crawlers coming soon

White peach scale (Pseudaulacaspis pentagona) is an armored scale common on many landscape plants and fruit trees. It has a wide host range including over a hundred plant genera such as Buddleia, Camellia, Clematis, Cornus, Euonymus, Hydrangea, Ilex, Ligustrum, Prunus, and many others. The most common host of samples submitted to the PDIC here at NCSU is cherry laurel (Prunus laurocerasus). Cherry laurel is an exotic species which of course is installed in nearly every new landscape I see.

White peach scale females and males on cherry laurel. Photo: SDF

Like most armored scales white peach scales are sexually dimorphic. The females are waxy bumps on twigs but the males grow wings and look like an actual insect. The males emerge from ‘pupal cases’ (not technically pupae). Twigs become covered with the fluffy white pupal cases. This is the easiest time to see and diagnose white peach scale infestations.

Of course the males come out to mate. Two weeks after the males emerge females will begin producing eggs and crawlers will start hatching. Scouting for the males, even though they do not feed, gives you a head start to plan your management approach.

White peach scales have 3 to 4 generations per year. Infestations are often concentrated on particular branches since scales do not move very far. Dense infestations can kill the individual twigs they are on. Minor infestations in landscapes should be monitored. You can probably inspect most cherry laurels and find some of these. That doesn’t mean you need to treat them; they can just hang out in low densities for years controlled by natural enemies. Plant stress and insecticide applications, like mosquito sprays, could increase the likelihood many armored scale species become problems.